What to do if your boiler loses pressure

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Certain issues with your boiler could be caused by a loss of pressure. A boiler which loses pressure is relatively easy to identify and in most cases is a simple fix you can do yourself without the need for a trained gas engineer. The heating experts at Fixx put together this handy guide to show you what to do if your boiler loses pressure. In our handy guide, we show you what to do if your boiler loses pressure, how to identify and fix the issue yourself and highlight when it is best to seek the help of a trained engineer.

What is Boiler Water Pressure?

Boiler water pressure refers to the pressure of hot water which runs in your sealed central heating system. For the boiler to operate efficiently, it is important the water pressure is at a consistent level for several reasons. For example, if the boiler pressure is too low then the system could cut out and prevent your central heating from work properly, but it won’t damage your boiler. On the other hand, if the boiler pressure is too high then, it will strain the system and could also stop it from working.

What Causes a Boiler to Lose Pressure?

There are two main reasons that can cause a boiler to lose pressure these are:

  1. Leaks – A leak in your boiler system will cause your boiler to lose pressure. Identify leaks around your home by looking for damp patches around your pipes, radiators and the boiler. Please note, you should NEVER look inside your boiler for leaks. Should you find a leak or need your boiler looking at always call one of our Gas Safe engineers to check your boiler.
  1. Bleeding radiators – If you’ve recently bled your radiators, then you may have lost some pressure. This is because when you bleed a radiator, the trapped air is released which lowers the boiler’s pressure.

What to do if your boiler loses pressure?

If your boiler is losing pressure, then you will need to re-pressurise it you can do this yourself, but before you go ahead and do so, it is always best to check your boiler manual first to see if you can re-pressurise the system yourself because each boiler system can differ and sometimes you may need a Gas Safe Registered engineer to do this. Please note, you can also visit your boiler brand’s website, to check if they have any tutorials on re-pressurising their boiler systems.

Firstly, you will need to check your boiler’s pressure. To do this you need to find your water pressure gauge this is usually located on the front of your boiler. The pressure gauge should read around 1 bar in the green zone when the boiler is switched off. However, when the boiler is functioning, the pressure should increase slightly, then it should drop back down. Should you find your boiler pressure is less than 1 bar, you will need to re-pressurise the boiler.

If your boiler manual states it is safe for you to re-pressurise the boiler yourself, then you can go ahead with the process. To re-pressurise your boiler it will usually compromise of the following steps:

  1. Locate the filling-loop and pressure gauge – Firstly, you will need to identify the filling loop and pressure gauge on your boiler. The pressure gauge can be found on the front of your boiler and the filling-loop handles should be at a 90° angle to the flow of the pipe.
  2. When accessing the filling loop you want to ensure you can see the pressure gauge. Usually most sealed systems will operate at around 1.0 – 1.5 bar, but you should always your manual for your specific system. On modern systems the correct pressure level will be shown on the gauge.
  3. Switch off your boiler
  4. On your boiler turn both filling loop handles to match the direction of the pipe. Once this has been down you should hear water flowing.
  5. Keep an eye on the pressure gauge to ensure you don’t over-pressurise the boiler. If you cannot see the pressure gauge whilst turning the filling-loop then you should get someone to assist you on this.
  6. Once the correct pressure has been reached on the gauge then you should make sure the handles are fully closed.
  7. Switch the boiler on and observe.

In the event you do accidentally over-pressurise the boiler don’t panic. To resolve this, you need to bleed your radiators to reduce the pressure and bring it back to the correct level. For more information on how to bleed a radiator read our helpful guide.

After re-pressurising the boiler, if the pressure remains the same then it is likely the problem is resolved and there is no need for further action. On the other hand, if you find the boiler continues to lose pressure then, it is likely you need the assistance of a qualified Gas Safe engineer. If you require our help please call us on 0330 3530 365 or simply contact us online we aim to get one of our professional, qualified and reliable Gas Safe engineers to your property asap.

Book an Annual Boiler Service with Fixx.

Do you need to book your boiler in for an annual service? It is important to have an annual boiler service to ensure your boiler is operating safely and efficiently to its maximum capacity minimising the risk of carbon monoxide poisoning. For more information on the importance of a boiler service here’s our 5 reasons to book an annual boiler service.

Here at Fixx we offer boiler services throughout the North of England. Call us on 0330 3530 365 and one of our friendly helpdesk advisers will book your boiler service in for a date and time that suits you and will minimise disruption to your day. Alternatively, you can use our online boiler service booking form to arrange your annual boiler service. 

All our Gas Engineers have the relevant qualifications, years of experience and are on the Gas Safe Register so, you can have peace of mind all boiler services carried out by our engineers are completed safely and efficiently to the highest standard.